The event was held at Horse Guard's Parade and the Mall in London and involved around 70 aircraft from the Royal Navy, British Army, and Royal Air Force.
The King rode on horseback for the first time in 30 years, since the late Queen rode her horse, Burmese, in 1986.
The Queen, the Princess of Wales, and their children also attended, as well as
Prince William and other senior royals.
The ceremony included music, marching, and an inspection of soldiers.
The event was also attended by Prime Minister Rishi Sunak, Labour leader Sir Keir Starmer, and prime ministers of Commonwealth states and realms.
The King's Troop, a ceremonial unit of the British Army, took part in a parade and shooting demonstration to mark the King's official birthday.
The parade took place in London and was followed by a 41-gun salute in Green Park and a firing of 62 volleys by the Honourable Artillery Company from the Tower of London.